Requiring unknown module "undefined"

Error after upgrading 0.54.0 from 0.53.3.

Requiring unknown module “undefined”.If you are sure the module is there, try restarting Metro Bundler. You may also want to run yarn, or npm install (depending on your environment). handleException @ ExceptionsManager.js:65 handleError @ InitializeCore.js:115 reportFatalError @ error-guard.js:44 guardedLoadModule @ require.js:141 _require @ require.js:130 executeApplicationScript @ debuggerWorker.js:40 (anonymous) @ debuggerWorker.js:65 ExceptionsManager.js:65 Module AppRegistry is not a registered callable module (calling runApplication)

Environment

Environment: OS: macOS High Sierra 10.13.3 Node: 8.9.4 Yarn: 1.5.1 npm: 5.6.0 Watchman: 4.9.0 Xcode: Xcode 9.2 Build version 9C40b Android Studio: 3.0 AI-171.4443003

Packages: (wanted => installed) react: ^16.3.0-alpha.1 => 16.3.0-alpha.1 react-native: 0.54.0 => 0.54.0

Expected Behavior

App should launch

Actual Behavior

UnknownModuleError

Steps to Reproduce

react-native run-android

[wildseansy]

I was able to resolve this issue for my project by doing the following…

Given that this issue seems to be caused when there is import {y} from './x' and import {z} from 'myapp/x' in the same file, I was able to track down these files with these steps:

1. Run your app until you get the error message
2. In the stack trace, click on the filename included from your project, under one of the _require items in the stack trace. See screenshot below:

Be sure you have set the REACT_EDITOR variable set so react-native can open the file with an editor

In my file (actions.js), before changes

import {
  getUserEmail
} from 'myapp/user/selectors';

import {
  getUserName
} from './selectors';  //<-- same file as 'myapp/user/selectors'. This is why metro crashes

actions.js after changes

// Change the above to: 
import {
  getUserEmail,
  getUserName
} from 'myapp/user/selectors';

This will also work:

// Or you can change it to: 
import {
  getUserEmail,
  getUserName
} from './selectors';

Now run your app again, and you may get the same error, but it will now point to a different file (assuming you have resolved all imports in the first file). If you get the error in a new file, repeat steps above until all files are cleaned up.

I had to do this 3-4 times before I had found all of the modules that have import {y} from './x' and import {z} from 'myapp/x' in the same file. Hope this helps someone else.

[HumanUndead]

It will work but its up to you